The use of digital input scanners, which can successively scan a set of sheets and record the images thereon as digital data, is becoming common in the office context, such as in digital copiers and electronic archiving. In any situation in which digital image data is created and accumulated in memory and/or transmitted through communication channels, it is desirable that the memory and the communication bandwidth are used in an efficient way. In particular, it would be good to avoid filling up the memory and the communication channels with redundant data.
A common type of input scanning in an office context is scanning and recording images from forms, slide presentations, or other documents in which multiple page images share a common “template” or appearance cues, such as logos, letterheads, and so forth. In a typical slide presentation, there is a standard template slide design, including for instance a logo and a border; among the slides only the text changes. The present embodiment is directed toward a technique for efficiently recording such documents in memory.